Study on the anomalies of thermoelectric power due to the normal-state pseudogap in underdoped cuprates

Abstract

The thermoelectric power of underdoped Gd 1-x Pr x Ba 2 Cu 3 O 7-δ with different Pr contents is measured. The experiments indicate that a hump in the temperature dependence of TEP appears above T c . This is considered to be associated with the opening of the normal-state pseudogap. The present experimental results and those reported by Tallon et al. [J.L. Tallon et al., Phys. Rev. Lett. 75 (1995) 4114.] are analyzed based on the opening of the pseudogap. The pseudogap excitation energy E G is obtained. Furthermore, a phase diagram of E G versus hole concentration p is given. The analysis may provide an effective way to estimate E G .